A graphical user interface is rendered on a display screen of a touch screen device. The display screen includes a display area for rendering images, and the graphical user interface of the application is rendered in a portion of the display area. Digital touch data is generated in response to user interactions with a touch-sensitive surface of the touch screen device. A module of an operating system residing on the touch screen device is used to convert the digital touch data into OS touch events. The OS touch events and application location information are received at a system hook. The application location information identifies the portion of the display area of the touch screen device in which the graphical user interface of the application is rendered. The system hook filters the OS touch events based on the application location information and provides the filtered OS touch events to the application.